Fluid pressure actuated cutting tool



9 19511 P. D. HOLOWKA 3 FLUID PRESSURE ACTUATED CUTTING TOOL Filed May 14, 1948 2 Sheets-Sheet 1 IN V EN TOR.

Z6 I f iza Feb. 27, 11951 P. D. HOLOWKA 2,543,1W9

FLUID PRESSURE ACTUATED CUTTING TOOL Filed May 14, 1948 2 Sheets-Sheet 2 n 6 D I 54 Z 4'] 5 Z 7 INVENTOR.

Patented Feb. 27, 1951 UNITED STATES ATENT OFFICE FLUID PRESSURE ACTUATED CUTTING TOOL 5 Claims.

This invention relates to a novel pruning tool or implement for cutting off limbs and branches of trees and bushes or which may be utilized for cutting roots and heavy undergrowth and more particularly has reference to a fluid actuated cutter for this purpose.

Still a further and important object of the present invention is to provide a fluid actuated cutting tool including a movable cutting blade actuated in response to a fluid pressure medium; said tool having automatically actuated bleeder means for dissipating the fluid pressure when the blade has reached a fully projected position for automatically releasing the fluid pressure on the blade after the cutting operation has been completed and to prevent damage to the tool.

Still a further object of the invention is to provide a tool or implement of the aforedescribed character having a novel valve control means for controlling the supply of the compressed medium.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

Figure l is a side elevational view, partly in longitudinal section showing the tool or implement with the blade in a retracted position;

Figure 2 is an enlarged longitudinal sectional 1 view taken substantially along a plane as indicated by the line 22 of Figure l Figure 3 is a sectional view taken substantially along a plane as indicated by the line 3-45 of Figure 2;

Figure 4 is a cross sectional view of the head of the tool taken substantially along a plane as indicated by the line 4-4 of Figure 1;

Figure 5 is an enlarged sectional view, partly in side elevation of a part of the conduit of the compressed medium including the release valve;

Figure 6 is a similar view of another part of the conduit including the manually controlled shutoff valve, and

Figure 7 is a cross sectional view of the tool taken substantially along a plane as indicated by the line 1-4 of Figure 1.

Referring more specifically to the drawings, the fluid pressure actuated cutting tool in its entirety is designated generally 8 and includes a frame or housing 9 formed of corresponding plates Ill having spacing strips H interposed between the side edges thereof and which plates 1!) are connected to one another and to the strips H by fastenings l2. The frame 9 is enlarged adjacent its outer end or head l3 and said head is provided with a laterally opening recess l4 adapted to receive a limb or other member l5 to be cut and whereby said head I3 is substantially hook-shaped and with the outer portion thereof defining a stationary jaw I6 against which the limb or'other member Hi to be cut, when disposed within the recess 14, will bear.

The strips H combine to space the plates ID from one another and are likewise spaced relatively to each other to form a guideway H extending longitudinally of the frame 9 and through the head 13 in which an elongated cutting blade IB is reciprocally disposed and guided.

; The cutting blade 18 is provided with a sharpand which has a piston rod 23 extending therefrom reciprocally through a stufiing box 2%, located in the end of the cylinder 2! adjacent to the head E3. The outer end of the piston rod 23 p is slotted to receive the opposite, inner end of the blade l8 and is secured thereto by fastenings 25 and is disposed to reciprocate in the end of the slot 26 located adjacent the head it. An expansion coiled spring 25 is disposed in the cylinder 20 between its inner end and the piston 22 for urging the piston rod 23 inwardly of the cylinder 2! for urging the blade [8 toward a retracted position, away from the head It.

A pipe or tube 2! is secured to and projects from the outer end of the cylinder 2! and from the complementary end of the frame 9 and is provided with an open opposite end. Said pipe or tube 21 forms a handle for the tool 8 and may be of any desired length. A generally T-shaped valve housing 28 is disposed in the pipe or tube El and has the lateral leg thereof extending outwardly through an opening 29 of the pipe 2'! for mounting the housing 28 therein. As best seen in Figure 6, the valve housing 28 is connected at its outer end to a flexible supply conduit 30 which extends into the tube 2l through the outer open end thereof and the opposite, discharge end of the housing 28 is connected by a flexible conduit 3i to the adjacentend of the cylinder 2i. intermediate of. the ends of the housing 28 is disposed two integral partitions or internal walls 32 and 33 provided with ports 34 and 35, respectively which are disposed in transverse alignment with respect to the longitudinal axis of the valve housing 28 and in alignment with the lateral branch 36 of said housing which extends through the opening 29. The partition 32 divides the inlet and outlet ends of the housing 28 connected to the conduits 30, 3|, respectively so that a medium passing from the inlet conduit 30 to the outlet conduit 3| must pass through the port 34. A valve 3! is disposed between the partitions or walls 32 and 33 and has a threaded valve stem 38 extending from one side thereof through the port 34 and longitudinally through the branch 36 of the valve housing 28 and outwardly thereof through a stufiing box, designated generally 39, in a portion of which the valve stem 38 is threadedly engaged. The outer end of the valve stem 38 which is disposed externally of the stuffing box 39 is provided with a hand wheel 48 for rotating the valve stem 38 for moving the valve 31 either toward or away from either of the ports 34 and 35 and it will be readily apparent that said valve 31 may be disposed in an intermediate position as seen in Figure 6 so that both of the ports 34 and 35 will be opened or may be moved to a position for closing either of said ports for a purpose which will hereinafter become apparent. The valve 3'! may be secured in any suitable manner to the stem 38 and may be applied to the housing 28 through the outlet port thereof. The valve housing 28 is also provided with a small lateral passage 4| which is T-shaped and which is adapted to be connected in a conduit 42, as best seen in Figure 1, for a purpose which will hereinafter be described. The branch conduit 4| extends from the main portion of the valve housing 28 in the opposite direction to the branch 36 and is disposed entirely within the tube 21 and communicates with the main portion of the housing 28 through the port 35 so that when the valve 31 is moved into engagement with the partition 33 for closing the port 35, said branch passage 4| will be closed.

As best seen in Figure 1, a conduit 43 has one end thereof communicating with the cylinder 2| adjacent its outer end and extends therefrom toward the head I3 and has its opposite end communicating with the inlet end 44 of a valve housing 45 which is supported on one side of the frame 9 adjacent the head I3 and which includes a substantially U-shaped outlet section 46 having a downwardly extending flanged leg which connects with the open upper end of the valve housing 45 and through which a valve stem 41 reciprocally extends. The valve stem 4'! extends upwardly and outwardly through the intermediate portion of the outlet conduit 46 which is provided with an opening containing packing as seen at 48 for reciprocally receiving the valve stem. A head 49 is disposed in the lower end of the valve stem 41 and which is adapted to engage and close the end of the conduit 46 which extends into the housing 45. An expansion coiled spring 50 which is contained in the housing 45 bears against and yieldably urges the valve 49 into engagement with the outlet conduit 46. The other downwardly extending leg of the outlet conduit 46 is connected to one end of the flexible conduit 42.

As best seen in Figure 1, a lever 52 is pivotally mounted at 53 intermediate of its ends on the head I3 on the same side of and above and ad- .lacent thevalve housing 45 and has one end 54 disposed to engage the outer end of the valve stem 41 but which is normally held out of engagement therewith by a contractile spring 55 which is anchored to the head I3 and connected to an extension 56 of the lever end 54 for normally drawing said end awa from the valve stem 41 and for causing the lever 52 to rock clockwise on its pivot 53 as seen in Figure 1. A screw 5! extends through the opposite end 58 of the lever 52 in a direction toward the piston rod 23 and is adapted to be adjustably secured to said lever end 51 by a nut 58, carried by the threaded shank of the screw. The slotted end of the piston rod 23 is provided with an outwardly opening notch 59 to receive the end of the screw 51 as the cutting edge i9 of the blade I 8 approaches a fully projected position in the head I6 and beyond the notch I4.

Any suitable compressed medium such as an hydraulic or a pneumatic medium under pressure could be utilized for operating the tool 8. For example, the conduit 36 could be connected to an orchard sprayer or the hydraulic pump of a tractor or to an air pump or a chamber containing a compressed fluid medium. Assumin that the implement parts are in the positions as shown in Figure 1 and with the limb I5 engaged in the notch i4 and against the head or stationary jaw I 6, the valve handle 40 is rotated to move the valve 3'! to a position for exposing the port 34 and to its other extremity so that it will close the port 35. With the valve 3'! thus disposed the compressed medium, not shown, will pass from the inlet or supply line 30 through the valve housing 28 and conduit 3| to the outer end of the cylinder 2|. As the valve 49 will be in a closed position, the compressed medium will be prevented from escaping from the cylinder 2| through the return line 42 and accordingly will force the piston 22 toward the opposite end of the cylinder 2| for projecting the blade I8 so that its cutting edge I9 will cut through the limb I5. As the cutting edge I9 passes entirely through the notch I4 and into the guideway of the stationary jaw IS, the notch 59 will engage the screw 58 for rocking the lever 52 counterclockwise as seen in Figure 1. This will cause the lever end 54 to exert a pressure on the valve stem 4! for moving the valve 49 downwardly in the housing 45 against the action of the springs 59 for exposing the outlet conduit 46 of the valve housing to permit the compressed medium in the cylinder 2| to escape therefrom through the conduits 4| and 42 thereby preventing the blade I8 and the piston rod 23 from moving beyond a fully projected position so that the piston rod 23 will be prevented from striking the frame 9 and the piston 22 will be prevented from compressin the spring 26 to too great an extent. When this movement of the blade and piston rod toward a projected position is thus interrupted, the operator turns the valve stem 38 for moving the valve 31 into a position for closing the port 34 so that the compressed medium in the cylinder 2| can escape back through the valve housing 28 and its branch 4| into the return line 42 since the valve 49 will return to a closed position as soon as the notch 59 moves out of engagement with the screw 5?. The force of the spring 25 will return the piston 22 to its position of Figure 1 for forcing the compressed medium therefrom through the branch conduit 4| and for returning the blade I8 to its fully retracted position of Figures 1 and 3. The return line 42 may be connected to a suitablereservoir'for an hydraulic medium or, where a pneumatic medium is utilized, said line may vent to the atmosphere.

Various modifications and changes are contemplated and may obviously be resorted to, without departing from the spirit or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. A cutting implement comprising a frame having a head provided with a laterally opening notch adapted to receive a member to be cut, said frame having a guideway extending through said head and to beyond said notch, a blade reciprocally disposed in said guideway and having a cutting edge at its leading end disposed for movement through said notch when the blade is moved from a retracted to a projected position for cutting through the member disposed in the notch, and afluid pressure actuated means mounted in said frame and including a reciprocally disposed pressure responsive element connected to the blade for moving said blade to a projected position in response to a fluid pressure exerted on said element and means including an element connected to the blade and actuated by the fluid pressure responsive element as the blade approaches a fully projected position for releasing the pressure on said element.

2. A cutting implement comprising a frame having a head provided with a laterally opening notch adapted to receive a member to be out, said frame having a guideway extending through said head and to beyond said notch, a blade reciprocally disposed in said guideway and having a cutting edge at its leading end disposed for movement through said notch when the blade is moved from a retracted to a projected position for cutting through the member disposed in the notch, and a fluid pressure actuated means mounted in said frame and including a reciprocally disposed pressure responsive element connected to the blade for moving said blade to a projected position in response to a fluid pressure exerted on said element, said fluid pressure responsive means including a cylinder fixedly supported in the implement frame, a piston reciprocally disposed in said cylinder, apiston rod connected to the piston and extending reciprocally through one end of the cylinder and connected to said blade, a supply line for the fluid pressure medium communicating with the opposite end of said cylinder, a valve interposed in said supply line for admitting the fluid pressure medium to the cylinder in one position of the valve and for permitting the fluid pressure medium to be dissipated from the cylinder in another position of the valve, a bleeder conduit connected to said cylinder adjacent its last mentioned end, a valve interposed in said bleeder line and normally disposed in a closed position, a lever pivotally mounted intermediate of its ends on the frame and having one end engaging the bleeder line valve, and an element carried by the piston rod for engaging the opposite end of the lever as the blade approaches a fully projected position for rocking the lever to open said bleeder line valve.

3. A cutting implement comprising a frame having a head provided with a laterally opening notch adapted to receive a member to be cut, said frame having a guideway extending through said head and to beyond said notch, a blade reciprocally disposed in saidguideway and having a cutting edge at its leading end disposed for movement through said notch when the blade is moved from a retracted to a projected position for cutting through the member disposed in the notch, a fluid pressure responsive actuating means mounted in said frame and including a reciprocally disposed pressure responsive element connected to the blade for moving the blade to a projected position in response to a fluid pressure exerted on the element, said fluid pressure responsive means including a bleeder line for bleeding off the fluid pressure medium, a normally closed valve mounted in said bleeder line, a lever pivotally mounted intermediate of its ends on the frame and having one end engaging said valve, and a projection on said pressure responsive element disposed to engage the other end of said lever as the blade approaches a fully projected position for rocking the lever to open the valve of the bleeder line.

4. A cutting implement as in claim 3, and a member adjustably carried by said last mentioned end of the lever and disposed to be engaged by the projection on the pressure responsive element for varying the time of opening of the bleeder valve with respect to the movement of the blade.

5. A cutting implement as in claim 3, said notch having a downwardly and outwardly inclined upper surface adapted to be engaged by the member to be cut, and said blade having a cutting edge at its leading end provided with inwardly converging portions for cooperation with the upper surface of the notch to retain the member to be cut in engagement with said notch when the blade is projected.

PAUL D. HOLOWKA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,366,909 Johnson Jan. 9, 1945 2,391,676 Browning Dec. 25, 1945 

